FIG. 1 shows a first conventional valved trocar jacket tube, wherein the conventional trocar jacket tube 1 comprises a cylindrical jacket 2 and a casing 3 secured to the top of the jacket 2. The casing 3 is provided with a circular opening 3a on the upper part thereof. Furthermore, the casing 3 contains a valve 4 for opening and closing the opening 3a on the inside thereof and a spring 5 for urging the valve 4 in the closing direction therein.
When the valved trocar jacket tube 1 thus constituted is employed, as shown in FIG. 2, the surgeon inserts the jacket 2 of the valved trocar jacket tube 1 into a site, for example, an abdominal incision Pa of a patient P being an object to be operated. In case of using a clamp (forceps) or the like 7, an adapter 6 called as reducer or introducer is used, which comprises a leakage preventing valve 6A having an opening 6a an inner diameter of which corresponds to an outer diameter of the clamp or the like 7 and an outer cylinder 6B. The surgeon sets the clamp or the like 7 having a diameter corresponding to the opening 6a of the adapter 6 thereto, and the adapter 6 is inserted through the opening 3a of the casing 3. In this case, the valve 4 is opened against the spring force of the spring 5 due to insertion of the adapter 6. As a result, leakage of an inert gas injected into an abdominal cavity for conducting easily endoscopy or the like is prevented.
According to the first conventional valved trocar jacket tube 1, however, there is a disadvantage in that since the diameter of the opening 3a provided on the casing 3 is constant, it is required to use an adapter 6 having the diameter corresponding to that of the clamp or the like 7 to be used, and the substitution to another adapter is troublesome, thereby preventing the operator's manipulation.
Further, there is another disadvantage in that since the standard sizes of the opening 6a of the adapter 6 are usually 5 mm, 10 mm, and 12 mm, a clamp or the like having an intermediate size such as 6 mm or 8 mm cannot be used, so that the sizes of the clamp or the like 7 are also restricted.
Still further, since the inner diameters of the openings 6a of the adapter 6 and the outer diameters of the clamp or the like 7 are nominal values, respectively, there is the other disadvantage in that the inner diameter of the opening 6a of the adapter 6 may not match with the outer diameter of the clamp or the like 7. As a result, it is impossible to use the clamp or the like 7 or it may cause leakage of the inert gas.
For solving these problems, the Applicant proposed a valved trocar jacket tube of another type in Japanese Patent Application No. 8-266883 (Japanese Patent Application Laid-Open No.10-108868) filed on Oct. 8, 1996, wherein the valved trocar jacket tube comprises a first cylindrical elastic member having an opening with a predetermined sectional area, a pair of rings, to which the ends of the first cylindrical elastic member are attached respectively, and which are so constructed that when they are rotated relatively in the opposite directions the opening of the first cylindrical elastic member is closed from the opening state, a second cylindrical elastic member to be inserted into an abdominal incision, one end of which is attached to one of the pair of rings, and a ring shaped elastic member provided at another end of the second cylindrical elastic member, which enlarges another end of the second cylindrical elastic member and contacts it closely to the abdominal incision.
According to the second conventional valved trocar jacket tube, when a pair of rings are rotated relatively in the opposite directions, an opening of a first cylindrical elastic member is closed due to the twist of the first cylindrical elastic member, so that it will fit securely and flexibly with the hands of the surgeon or the clamp or the like, which is preliminarily inserted into a incised portion of a diseased part through the opening. As a result, the types of clamps or the like to be employed are not limited and it is possible to use the clamps of the intermediate sizes or the clamps having contours other than a circular shape. Further, since the use of an adapter becomes unnecessary, it is not necessary to conduct substituting operation of the adapter, so that endoscopic surgery can be conducted smoothly. Still further, since the second cylindrical elastic member fits securely with an abdominal incision due to the tension thereof, the airtightness of an abdominal cavity can be kept and leakage of an inert gas from the abdominal cavity can be prevented.
On the other hand, U.S. Pat. No. 5,366,478 discloses a valved trocar jacket tube of the other type. This third conventional valved trocar jacket tube contains a pair of ring-shaped elastic members on the inside thereof and comprises a cylindrical air container having an opening provided at the central portion thereof, in which the opening section is changed to have a predetermined sectional area from the closed state due to injection of an air. This valved trocar jacket tube is such constructed that one of the pair of the ring-shaped elastic members is inserted into an abdominal cavity through an abdominal incision and air is injected into the cylindrical air container, so that the cylindrical air container fits securely to the abdominal incision.
According to the second conventional valved trocar jacket tube proposed by the Applicant, however, since the contacting force is determined in accordance with an outer diameter of the second cylindrical elastic member and the contour of the abdominal incision, when the contour of the abdominal incision becomes relatively large, the contact between the second cylindrical elastic member and the abdominal incision becomes insufficient, so that an inert gas is leaked from a gap defined by the second cylindrical elastic member and the abdominal incision.
On the other hand, according to the third conventional valved trocar jacket tube disclosed in U.S. Pat. No. 5,366,478, when the hand of the surgeon or the clamps or the like is inserted into an abdominal cavity or it is pull out therefrom, it is necessary to adjust the volume of an air injected into an air container. It is troublesome to conduct such an adjustment of the air volume for several times during the surgery, and it is impossible to avoid the leakage of an inert gas from the abdominal cavity at this time. Further, in view of decreasing the leakage of the inert gas to the minimum, if the air volume of the cylindrical air container is not reduced so much, the inserted hand or clamp or the like may scratch the cylindrical air container, and when the things come to the worst, it may be damaged.